Alek Petkovic wrote:
>You must also remove the two reluctance slugs that are wedged into the
>core. Not sure what they do but you don't want them in there for your
>ht supply.
>
In effect they make the transformer current-limiting, and indeed you
don't want that. The slugs were force-fitted, so with a hammer and a big
punch you can drive them out.
>A better option is to have 2 identical transformers and run the
>primaries in parallel and the secondaries in series in a grounded
>centre tapped configuration. This does away with the risk of the ht
>flashover.
>
True, but it still leaves each transformer operating as a half-wave
rectifier, with a net DC current flowing through the windings as well as
the AC component. This takes the core much closer to saturation.
>There is another disadvantage with these transformers. The core
>laminations are generally welded. I think that this results in
>increased core losses and heating.
>
These transformers are designed "close to the edge" in every way, to
keep the cost down - just compare the size and weight of them with the
transformer you'd normally use in a PA that has the same power output as
a microwave oven. They're undoubtedly better than no transformer at all,
but not as good as the ones we normally use.
--
73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB)
Editor, 'The VHF/UHF DX Book'
http://www.ifwtech.co.uk/g3sek
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